Caption: Nuclear test crater. Sedan Crater, the result of the underground detonation of a nuclear bomb at the Nevada Test Site, USA, on 6 July 1962. The explosion was equivalent to 104 thousand tonnes (kilotonnes) of TNT explosive. The explosion occurred 194 metres underground and displaced around 12 million tonnes of earth. The crater is 98 metres deep and 390 metres in diameter. The bomb was detonated as part of the Plowshare programme which studied nuclear explosions to develop peaceful uses for atomic energy. The Sedan crater was the largest created during this programme.